import std.stdio, std.array, std.string, std.conv, std.algorithm; import std.typecons, std.range, std.random, std.math, std.container; import std.numeric, std.bigint, core.bitop, core.stdc.stdio; void main() { auto s = readln.split.map!(to!int); auto n = s[0]; auto k = s[1] - 1; auto X = readln.split.map!(to!long).array; auto A = readln.split.map!(to!long).array; DList!(Tuple!(long, long)) qmin; DList!(Tuple!(long, long)) qmax; foreach (i; 0..k) qmin.insertBack(tuple(X[i], A[i])); foreach (i; k+1..n) qmax.insertBack(tuple(X[i], A[i])); int ans = 0; DList!(Tuple!(long, long)) que; que.insertBack(tuple(X[k], A[k])); long mx = -1; long mn = 1L << 59; while (!que.empty) { ans += 1; auto t = que.front; que.removeFront; auto x = t[0]; auto a = t[1]; mx = max(mx, x + a); mn = min(mn, x - a); while (!qmin.empty && qmin.back[0] >= mn) { que.insertBack(qmin.back); qmin.removeBack; } while (!qmax.empty && qmax.front[0] <= mx) { que.insertBack(qmax.front); qmax.removeFront; } } ans.writeln; }